This invention relates to a projectile for use in virtually any firearm, and, in particular, a projectile which is designed to achieve a higher velocity and flatter trajectory, and therefore, increased transference of energy to the target and accuracy over both long and short ranges.
As long as firearms have existed, there have been those who have made and experimented in the manufacture of bullets and projectiles. The jacketed projectile, because it is comprised of at least two elements, the jacket and the core, has undergone a substantial amount of this experimentation. Over the years, enthusiasts and commercial manufacturers have combined various substances in the manufacture of projectiles including wood, plastics, and metals, with further variations based on different types of metals having varying degrees of hardness, specific gravity, and mass. For instance, U.S. Pat. No. 867,508 discloses a projectile composed of a hard outer casing with an inner core composed of a softer metal oriented to the rear of the core and a lighter substance such as wood located in the nose of the core. Further U.S. Pat. No. 4,338,862 discloses a projectile having a low density filler in the nose portion of the core, preferably composed of plastic, to achieve a more destructive projectile with the characteristic of "tumbling" earlier in its path through the target.
The different types of metals utilized in projectile manufacturing vary from lead and copper to steel and tungsten. The velocity of a projectile of a particular size can be increased (at the same safe pressure levels) by using metals of lower specific gravity in the projectile. The benefits of greater velocity are well known in the art and, as noted above, include a flatter trajectory and greater accuracy and energy transference. The highest velocity of any projectile presently known to Applicant is that of the 220 Swift 0.22 caliber bullet having a calculated velocity (at the muzzle) of 4110 feet per second; actual velocity is somewhat less.
There are, however, limitations that restrict one from utilizing the lightest metal, e.g., the metal with the lowest specific gravity, available for bullets. Historically, the problem has been one of selecting a metal of sufficiently low specific gravity while maintaining a sufficient degree of hardness. Nevertheless, in spite of its relatively high specific gravity, lead is most commonly used as the core material because of its ductility, e.g., its ability to be formed by application of pressure, which enables the lead to move and assume a particular shape as the jacket and core move through the different steps of making the bullet. Without sufficient movement of the core in the jacket, the projectile may not form properly during manufacture or may fail to maintain the proper configuration prior to or after firing. For instance, the relatively soft metal copper, which is almost universally utilized as the bullet jacket, is easily deformed during the manufacturing process when a relatively harder metal, such as aluminum, is implanted into the jacket in a solid form. Consequently, if it is desired to use a core made from a metal which is harder than copper, the core must be pre-formed for insertion into the copper jacket.
The bullet of the present invention, however, overcomes this relative hardness problem and provides a bullet which, depending on the particular powder utilized, has an actual (measured) velocity (4300 f.p.s.) which is higher than that of the muzzle velocity of the above-described 220 Swift 0.22 caliber bullet and in the larger 0.30 caliber (30-06). In another experiment, a bullet made in accordance with the present invention was fired from a 0.357 magnum hand gun with a measured velocity of 2600 ft/sec (normal velocity is about 1200 ft/sec), with increased accuracy, without any indication of pressure problems, and with reduced recoil. The present invention provides a method of forming the metal core of the bullet, even for metals which are harder than the copper jacket, without the need for melting the metal by folding or rolling thin sheets of the metal, inserting them into the jacket, and then compressing or seating the rolled or folded metal sheet in the jacket. The result is a compressed core of the metal which is formed within the jacket by pressure without significant deformation of the jacket.
The advantages of the present invention are several. Not only are higher velocities achieved at the same safe pressure levels for a bullet of given caliber because of the reduced weight of the bullet, but so also is accuracy improved over comparable conventional lead core bullets because the reduced weight of the core allows a bullet of the same weight to be longer in length, having more bearing surface with the lands and grooves of the barrel of the firearm. Also, trajectory is improved by the aerodynamics of the longer bullet and the more pointed nose, or greater ogive, compared to that of conventional bullets of the same weight and having a lead core. Further, energy transference is greater on impact than that of known, conventional lead core bullets because of the higher velocity achieved over the same surface area at point of impact.